scholarly journals Comparison of Corrosion Behaviors of Bare Ti and TiO2

2019 ◽  
Vol 3 (4) ◽  
pp. 235-240 ◽  
Author(s):  
Ali Döner
Keyword(s):  
Electrochemical Impedance ◽  
Protective Layer ◽  
Cathodic Current ◽  
X Ray ◽  
Corrosion Behaviors ◽  
Bare Titanium ◽  
Alkaline Corrosion ◽  
Current Potential ◽  
Anodization Method

In this study, titanium (Ti) surface was anodized by applying 60 voltages for two hours to form titanium dioxide (TiO2) with anodization method. After anodization procedure, comparison of corrosion behaviors of the bare titanium and TiO2 coated titanium was examined in 1 M KOH solution by using electrochemical methods such as anodic and cathodic current-potential curves and electrochemical impedance spectroscopy (EIS). Cyclic voltammetry (CV) and energy dispersive X-ray (EDX) were used to characterize bare Ti and anodically formed TiO2 surfaces. According to obtained results, Ti surface was smooth and compact. However, surface structure of TiO2 coated titanium was porous and nanotubes formed on the surface. This porous structure which has protective layer contributed to increase the corrosion resistance. Higher polarization resistance was obtained on porous TiO2 than that of bare titanium. Besides, this protective layer bore well against the alkaline corrosion during long-term immersion.

scholarly journals Role of Vanadium Additions on the Corrosion Mitigation of Ti-6Al-xV Alloy in Simulated Body Fluid

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 903 ◽  
Author(s):  
El-Sayed M. Sherif ◽  
Sameh A. Ragab ◽  
Hany S. Abdo
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Immersion Time ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cyclic Potentiodynamic Polarization ◽  
Elemental Analyses ◽  
Corrosion Behaviors

The manufacturing of different Ti-6Al-xV (x = 2, 4, 6, and 8 wt.%) alloys using a mechanical alloying technique was reported. The corrosion behaviors of these newly fabricated alloys after 1, 24, and 48 h exposure to a simulated body fluid (SBF) were assessed using cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, and chronoamperometric measurements. Surface morphology and elemental analyses after corrosion for 48 h in SBF were reported using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) examinations. An X-ray diffraction investigation characterized the phase analyses. All results indicated that the increase of V content significantly decreases both uniform and pitting corrosion. This effect also increases with prolonging the immersion time to 48 h before measurement.

scholarly journals Effect of Temperature on the Corrosion Behavior of Biodegradable AZ31B Magnesium Alloy in Ringer’s Physiological Solution

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 591 ◽  
Author(s):  
Sebastian Feliu ◽  
Lucien Veleva ◽  
Federico García-Galvan
Keyword(s):  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Physiological Solution ◽  
Corrosion Layer ◽  
Effect Of Temperature ◽  
X Ray ◽  
Ringer’S Solution ◽  
Corrosion Behaviors ◽  
Az31b Alloy ◽  
Increasing Temperature

In this work, the corrosion behaviors of the AZ31B alloy in Ringer’s solution at 20 °C and 37 °C were compared over four days to better understand the influence of temperature and immersion time on corrosion rate. The corrosion products on the surfaces of the AZ31B alloys were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) provided information about the protective properties of the corrosion layers. A significant acceleration in corrosion rate with increasing temperature was measured using mass loss and evolved hydrogen methods. This temperature effect was directly related to the changes in chemical composition and thickness of the Al-rich corrosion layer formed on the surface of the AZ31B alloy. At 20 °C, the presence of a thick (micrometer scale) Al-rich corrosion layer on the surface reduced the corrosion rate in Ringer’s solution over time. At 37 °C, the incorporation of additional Mg and Al compounds containing Cl into the Al-rich corrosion layer was observed in the early stages of exposure to Ringer’s solution. At 37 °C, a significant decrease in the thickness of this corrosion layer was noted after four days.

scholarly journals Gum Arabic Nanoparticles as Green Corrosion Inhibitor for Reinforced Concrete Exposed to Carbon Dioxide Environment

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7867
Author(s):  
Mohammad Ali Asaad ◽  
Ghasan Fahim Huseien ◽  
Mohammad Hajmohammadian Baghban ◽  
Pandian Bothi Raja ◽  
Roman Fediuk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Reinforced Concrete ◽  
Electrochemical Impedance ◽  
Protective Layer ◽  
Gum Arabic ◽  
Steel Reinforcement ◽  
X Ray ◽  
Transmission Electron ◽  
Carbonation Resistance

The inhibiting effect of Gum Arabic-nanoparticles (GA-NPs) to control the corrosion of reinforced concrete that exposed to carbon dioxide environment for 180 days has been investigated. The steel reinforcement of concrete in presence and absence of GA-NPs were examined using various standard techniques. The physical/surface changes of steel reinforcement was screened using weight loss measurement, electrochemical impedance spectroscopy (EIS), atomic force microscopy and scanning electron microscopy (SEM). In addition, the carbonation resistance of concrete as well screened using visual inspection (carbonation depth), concrete alkalinity (pH), thermogravimetric analysis (TGA), SEM, energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The GA-NPs inhibitor size was also confirmed by transmission electron microscopy (TEM). The results obtained revealed that incorporation of 3% GA-NPs inhibitor into concrete inhibited the corrosion process via adsorption of inhibitor molecules over the steel reinforcement surface resulting of a protective layer formation. Thus, the inhibition efficiency was found to increase up-to 94.5% with decreasing corrosion rate up-to 0.57 × 10−3 mm/year. Besides, the results also make evident the presence of GA-NPs inhibitor, ascribed to the consumption of calcium hydroxide, and reduced the Ca/Si to 3.72% and 0.69% respectively. Hence, C-S-H gel was developed and pH was increased by 9.27% and 12.5, respectively. It can be concluded that green GA-NPs have significant corrosion inhibition potential and improve the carbonation resistance of the concrete matrix to acquire durable reinforced concrete structures.

Long-Term SOFCs Button Cell Testing

2013 ◽  
Vol 11 (2) ◽  
Author(s):  
Gianfranco DiGiuseppe ◽  
Li Sun
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Current Density ◽  
Electrochemical Impedance ◽  
X Ray ◽  
Total Polarization ◽  
Scanning Electron

This paper reports a new study where relatively long-term tests of about a 1000 h are performed on several planar anode-supported solid oxide fuel cells. The cell electrochemical behaviors are studied by using voltage-current density measurement, electrochemical impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The cell total polarization obtained from electrochemical impedance spectroscopy results is shown to be consistent with the area-specific resistance calculated from the voltage-current density curve over the course of the test. In addition, a four-constant phase element model is used to analyze the cell components resistances at different intervals over the lifetime of the test. Scanning electron microscopy and energy-dispersive X-ray spectroscopy are used postmortem to determine if any damages occurred to the cells and to determine if any change in composition occurred to the lanthanum strontium cobalt ferrite cathode. This study shows that the tested cells remain stable with a relatively small increase in the cell total polarization but with no increase in ohmic resistance.

scholarly journals Long-Term Atmospheric Aging and Corrosion of Epoxy Primer-Coated Aluminum Alloy in Coastal Environments

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 237
Author(s):  
Tianyu Zhang ◽  
Teng Zhang ◽  
Yuting He ◽  
Sheng Zhang ◽  
Binlin Ma ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Electrochemical Impedance ◽  
Synergistic Effects ◽  
Fractal Dimensions ◽  
Weather Conditions ◽  
X Ray ◽  
Epoxy Primer ◽  
Atmospheric Exposure ◽  
Effects Of Aging

Aircraft are subjected to extreme weather conditions in coastal areas. This study reports long-term atmospheric exposure tests carried out on an epoxy primer-coated aluminum alloy in a coastal environment for 7, 12, and 20 years. The micromorphology and characteristics of the section and surface, the products of corrosion, electrochemical impedance, and molecular structure of the coated specimens were examined through a spectrophotometer, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectrometer (XPS). The results showed that the angles of contact of the specimens with different numbers of years of atmospheric exposure satisfied the normal distribution. Their fractal dimensions increased with an increase in the duration of exposure. Intergranular corrosion and exfoliation corrosion appeared in the specimens after 20 years, where the product of corrosion was Al(OH)3. The impedances and thermal properties of the epoxy coatings were influenced by the synergistic effects of aging and post-curing. The impedances of the coatings decreased greatly after long-term atmospheric exposure. After 20 years of corrosion, the specimen showed the characteristics of the substrate being corroded. The mechanism of corrosion and the electrochemical equivalent circuit were also analyzed.

scholarly journals Influence of Ti Substitution on Electrochemical Performance and Evolution of LiMn1.5−x Ni0.5TixO4 (x = 0.05, 0.1, 0.3) as a High Voltage Cathode Material with a Very Long Cycle Life

Inorganics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 10
Author(s):  
Svetlana Niketic ◽  
Chae-Ho Yim ◽  
Jigang Zhou ◽  
Jian Wang ◽  
Yaser Abu-Lebdeh
Keyword(s):  
Energy Density ◽  
High Voltage ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
High Energy ◽  
High Energy Density ◽  
Partial Substitution ◽  
High Temperature Stability ◽  
X Ray

The high voltage spinel material LiMn1.5Ni0.5O4 (LMNO) has the potential to increase the energy density of lithium batteries. However, its battery performance suffers from poor long-term cycling and high-temperature stability. In order to overcome these limitations, we have studied the effect of partial substitution of Mn with Ti and LiMn1.5−x Ni0.5TixO4 (x = 0.05, 0.1, 0.3), LMNTO, materials have been synthesized in a newly modified sol-gel method and then characterized by TEM, SEM (EDX), AC Electrochemical Impedance Spectroscopy and Soft X-ray Spectromicroscopy. We have demonstrated that the long-term cycling limitation with these types of materials can be resolved and herein 2000 cycles at a high C-rate have been demonstrated in half cells. We have attributed this behavior to a possible charge compensation mechanism as evidenced by a Soft X-ray Spectromicroscopy study of delithiated LMNTO materials. This work takes high energy density batteries based on high voltage spinel material one step further towards commercialization, and it is believed that further improvement can be achieved using new electrolyte formulations.

Pitting corrosion and crevice corrosion behaviors of titanium alloy overlapped with aluminized PVC film in neutral salt spray

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Longfei Xie ◽  
Wenlong Zhou ◽  
Shiwen Zou ◽  
Xuesong Fu
Keyword(s):  
Crevice Corrosion ◽  
Graphical Model ◽  
Electrochemical Impedance ◽  
Galvanic Corrosion ◽  
Salt Spray ◽  
Corrosion Mechanism ◽  
Neutral Salt ◽  
X Ray ◽  
Pvc Film ◽  
Corrosion Behaviors

Abstract This paper presents a research on the corrosion behavior of Ti-15-3 alloy overlapped with aluminized PVC film in salt spray. It was found that severe corrosion occurred on aluminized PVC film in the coupled regions because of crevice corrosion and/or galvanic corrosion whereas Ti-15-3 alloy in the coupled regions experienced minor corrosion. Scanning electron microscope and Energy-dispersive X-ray spectroscopy analyses demonstrated the corrosion products adhered to the surface of Ti-15-3 alloy within the crevice. To evaluate the effect of aluminized PVC film on the crevice corrosion of Ti-15-3 alloy in salt spray condition, it is necessary to compare with the corrosion resistance of Ti-15-3 overlapped with polytetrafluoroethylene (PTFE) in different neutral salt spray. Further, the tests were performed by electrochemical impedance spectroscopy and potentiodynamic polarization. Combining the graphical model, an in-depth understanding of the crevice and galvanic corrosion mechanism of Ti-15-3 alloy overlapped with aluminized PVC film has been revealed.

scholarly journals Corrosion inhibition of austenitic stainless steel by clay in polluted phosphoric acid with presence of SiC abrasif

2018 ◽  
Vol 149 ◽  
pp. 01049 ◽  
Author(s):  
S. Skal ◽  
Y. Kerroum ◽  
Y. El Aoufir ◽  
A. Guenbour ◽  
A. Bellaouchou ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Phosphoric Acid ◽  
Electrochemical Impedance ◽  
Protective Layer ◽  
Corrosion Damage ◽  
Electrochemical Process ◽  
Solid Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Corrosive Environments

Stainless steels have many properties mechanical and chemical resistances resulting from the formation of the protective layer (passive film) on their surface which prevents the metal to react with corrosive environments such as, phosphoric acid. This acid contains various impurities, including agressive agents and solid particles of gypsum, increase the risk of corrosion damage depending on the type of stainless steel used. In addition, it has been show that abrasion-corrosion causes an acceleration electrochemical process leading to a decrease in the resistance of materials. This work is to find a solution through an ecological inhibitor. That why we have been studied the effect of crude clay on corrosion behavior of Alloy 31 in polluted phosphoric acid with abrasive by electrochemical impedance spectroscopy (EIS) . The clay was characterized by X-ray fluorescence spectroscopy (FX), X-ray diffraction (DRX) and infrared spectroscopy (IR). EIS exhibited that resistance of Alloy 31 increased with increase the concentration of inhibitor.

scholarly journals Effect of High Temperature Sodium Hydroxide Immersion on Fusion Bond Epoxy Coating

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Amal Al-Borno ◽  
Xianyi Chen ◽  
Shailesh Kewaldas Dhoke
Keyword(s):  
Sodium Hydroxide ◽  
Electrochemical Impedance ◽  
Analytical Techniques ◽  
Attenuated Total Reflection ◽  
Low Molecular Weight ◽  
Scanning Calorimetry ◽  
Premature Failure ◽  
X Ray ◽  
Deposit Layer

Fusion Bond Epoxy (FBE) coating system was exposed to 5% sodium hydroxide at elevated temperature for 30 days. The result of exposure showed formation of adhere deposit layer, a discolored zone underneath and remaining un-affected bulk of the coating. The deterioration of the coating was characterized using analytical techniques like scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX) spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), pull-off adhesion, and electrochemical impedance spectroscopy (EIS). Results obtained indicated chemical deterioration of the coating in the discolored zone and leaching of low molecular weight coating component forming deposit layer. Although the adhesion strength and barrier property were not affected, the polymer matrix in the affected zone undergoes severe changes in its surface microstructure, primary chemical structure, and glass transition temperature. This may inflict serious impairment of the coating functional properties and premature failure of the coating in long term exposure.

Electrochemical stability of Sm0.5Sr0.5CoO3−δ-infiltrated YSZ for solid oxide fuel cells/electrolysis cells

2015 ◽  
Vol 182 ◽  
pp. 477-491 ◽  
Author(s):  
Hui Fan ◽  
Minfang Han
Keyword(s):  
Electrochemical Impedance ◽  
Xrd Analysis ◽  
Oxygen Electrode ◽  
Composite Electrodes ◽  
Constant Voltage ◽  
Infiltration Process ◽  
X Ray ◽  
Sem Micrograph ◽  
Electrolysis Mode

Composite SSC (Sm0.5Sr0.5CoO3−δ)–YSZ (yttria stabilized zirconia) oxygen electrodes were prepared by an infiltration process. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) of the composite electrodes showed the formation of SSC perovskite and a well-connected network of SSC particles in the porous YSZ backbone, respectively. The electrochemical performance of the cell was investigated under both fuel cell and steam electrolysis modes using polarization curves and electrochemical impedance spectroscopy (EIS). The cell experienced a large degradation rate at 700 °C with a constant voltage of 0.7 V for over 100 h under power generation operation. The subsequent post-cell SEM micrograph revealed that agglomeration of the infiltrated SSC particles was possibly the cause for the performance deterioration. Furthermore, the long-term stability of the cell was examined at 700 °C with a constant voltage of 1.3 V under steam electrolysis mode. SEM associated with energy dispersive X-ray spectroscopy (EDS) was employed to characterize the post-test cell after the long-term electrolysis operation and it indicated that besides the agglomeration of SSC particles, the delamination of the SSC–YSZ oxygen electrode from the YSZ electrolyte, as well as segregation of cobalt-enriched particles (particularly cobalt oxides) at the interface, was probably responsible for the cell degradation under the steam electrolysis mode.

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